No president of the United States has ever attracted as much trust and affection from African-Americans as Bill Clinton. They felt comfortable with him, and he with them. More than any of his predecessors, he convinced them that he really understood and cared about them. Above all, he did not condescend to them. So at ease did he seem with America's black minority, so open and sincere in his defence of their rights, that Toni Morrison, winner of the 1993 Nobel prize for literature, chose to describe him as the country's "first black president".
But now the love affair is over, a casualty of the bitter battle for supremacy between Hillary Clinton and a genuinely black aspirant to the presidency. And the reason it has soured is not the predictable appeal of Barack Obama to his fellow African-Americans, but the disillusionment generated by the shabby way the Clinton camp has conducted its campaign.
It was Bill Clinton himself who started the rot by implying in his comments on Obama's victory in South Carolina that any African-American candidate would have won there, as Jesse Jackson once did - in other words, that Obama was just a marginal candidate who, like Jackson, garnered votes from African-Americans because of the colour of his skin. Not only was Clinton wrong about that, as Obama's support among white Americans has proved; he left many African-Americans feeling betrayed, their hero suddenly seeming no more than an old-time white politician exploiting racial prejudices for electoral gain.
Then there was Hillary's television advertisement about whom Americans would trust to answer the red telephone if it rang in the White House at 3am. The ad, showing vulnerable white children asleep in their beds, suggested that Hillary, with her White House experience, would be better equipped than her Democratic rival to protect them from danger. There was nothing overtly racist about this, but in the view of Orlando Patterson, a Harvard professor of sociology who has spent his life studying racism in America, it carried an unmistakable "racist sub-message".
Writing this week in the New York Times, he said that the ad played on the deep-rooted white American fear of the black man as a secret enemy. "The message: our loved ones are in danger, and only Mrs Clinton can save them," he claimed. "An Obama presidency would be dangerous - and not just because of his lack of experience. In my reading, the ad, in the insidious language of symbolism, says that Mr Obama is himself the danger, the outsider within."
Whether this interpretation is correct or not - and personally, I find it convincing - there is the additional fact that during the same weekend that the ad was aired, Hillary Clinton refused to quash unequivocally the rumours that Obama was a Muslim, even though she must have known perfectly well that he is not, or indeed to explain why it would have been so bad if he were.
All of this, however, palls before the grotesque intervention of her supporter Geraldine Ferraro, the former vice-presidential candidate. Ferraro (who was forced to resign from Hillary's campaign team because of her remarks) said in a press interview that Obama's success in the campaign was due to the fact that he was black. "If Obama was a white man, he would not be in this position," she said. "And if he was a woman, he would not be in this position. He happens to be very lucky to be who he is."
Obama retorted that he didn't think either his colour or his name could be listed as assets in his campaign for the presidency, and it would be difficult to disagree with him. Ferraro was obviously talking rubbish.
What she was also doing, as the Clintons had been doing less explicitly, was trying to undermine Obama's impressive efforts to rise above America's history of racial division and present himself as a unifying candidate. In their desperation to halt his rise, they have sought to persuade voters that he is trading on his blackness, whereas in fact he has been doing his utmost to transcend it.
The sad thing is that the Clintons are so terrified of losing their new chance of power that they are prepared to squander one of the finest achievements of Bill Clinton's presidency in order to prevail in the Democratic race. They don't deserve to succeed, and I hope they won't.